Not long after the transit tunnels of Muni and Bart went in below Market Street in the '70s, a San Franciscan butterfly â the Western Tiger Swallowtail (Papilio rutulus) discovered an ecosystem freshly lined with one of its larval food, or host trees: the London Plane sycamore (Plantanus acerifolia). Males fly among the treetops, females lay eggs on the leaves, caterpillars feed and pupate, and adult butterflies emerge. This creature's entire lifecycle has played out for years unheralded by the thousands who walk below this canopy daily. As the city re-imagines our grandest boulevard with the Better Market Street Project, join us for this evening and learn about a creature that seems to be keeping up in this human-altered landscape. Add your two cents to this fascinating convergence of city coexistence. Lepidopterists and artists Amber Hasselbring and Liam O'Brien will "tell the tale of a swallow-tail" and propose novel ideas of connecting our two species.